Bridges help define culture. They are among its most visible expressions of public works
in a technological age. American bridges of steel and concrete characterize
the rise of the United States as a powerful industrial nation, beginning after
the Civil War with the completion of the Eads Bridge (1874), a steel-arch
bridge designed by James B. Eads that spans the Mississippi River in St. Louis,
and the Brooklyn Bridge (1883), a steel-wire-cable suspension bridge designed
by John A. Roebling that spans New York City's East River. Each was, at the
time it was built, the longest-spanning bridge of its type and the first to
use steel. But the Brooklyn Bridge was more than a technical triumph; it also
became a cultural symbol demonstrating that engineering designs could be works
of structural art as well as a stimulus to other art forms, an idea illustrated
in paintings by Joseph Stella and in Hart Crane's great poem The Bridge
(1930).

National self-confidence created a series of major works in steel during
the first half of the twentieth century including the Bayonne Bridge (1931;
a steel-arch between New York and New Jersey) and the George Washington Bridge
(1931; a suspension bridge over the Hudson River in New York City), again
the longest-spanning of their type then and both designed by Othmar Ammann.

Self-confidence was shaken in 1940 with the failure of the recently completed
Tacoma Narrows Bridge in Washington in a relatively mild windstorm. This bridge
followed the design of the George Washington Bridge by including very little
deck stiffness, which led to the Tacoma collapse and to the instability of
other bridges built in the 1930s such as the Golden Gate (San Francisco),
the Bronx Whitestone (New York City), and the Deer Island (Maine). All of
these have been subjected to considerable stiffening since 1940, but none was
as narrow as the long-span Tacoma Bridge. This basic design problem was solved
by Ammann in his 1964 Verrazano-Narrows Bridge (New York City) and by British
designers of the Severn Road Bridge (England) in that same year.

Between 1883 and 1964 America led the world in steel-bridge design, especially
with suspension bridges. Roebling's Brooklyn Bridge had diagonal stays to
prevent the type of wind oscillations that destroyed the Tacoma Bridge. For
the 1903 Williamsburg Bridge (New York City), the engineers did not use diagonal
stays and instead designed a deep truss. This ugly design, heavily criticized,
led to the lighter design of the Manhattan Bridge (1909; New York City).

In 1926 the Delaware River Bridge connected Philadelphia, Pennsylvania,
and Camden, New Jersey, in time for the sesquicentennial celebration in Philadelphia.
At the time it was the longest-spanning suspension bridge in the world at
1,750 feet (533 m), which Ammann exactly doubled for his George Washington
Bridge.

The early twentieth century brought in reinforced-concrete bridges, of
which the most prominent were arches such as the Connecticut Avenue Bridge
in Washington, D.C. (1904), and the Westinghouse Bridge in Pittsburgh (1931).
The latter was at the time the longest-spanning concrete bridge in the United
States with a span of more than 400 feet (122 m) and represents a design that
still reflected the imitative forms of ancient bridges. The towers are fake
and the arcades inessential. Such extraneous effects disappear with the Russian Gulch
Bridge (1940; California), America's finest of its type at the time.

In American culture, concrete bridges presented a two-part problem. First,
they encouraged owners to seek architectural embellishments because concrete
could be cast in the field in custom forms; second, these bridges, when built
in profusion after World War II, encouraged cost-conscious engineers to create
structurally inarticulate forms in standardized shapes. Thus there arose two
ideas about concrete bridges. On the one hand, where owners considered beauty
to be crucial, designers sought architectural ideas of decoration; on the other
hand (and because of costly form work), where designers thought only of economy
the results were at best bland. These conditions prevented Americans from
drawing on the inspiration of the great European bridge designers Robert Maillart
and Eugene Freyssinet, whose ideas focused on economy and elegance. Nevertheless,
after World War II the state of California, under bridge engineer Arthur Elliot,
completed a series of exceptional designs mostly using the new development,
prestressed concrete. Examples of such works are the Adams Avenue overpass,
the old Miramar Bridge, and the Lilac Road Bridge all just north of San Diego.

A particularly significant design is the San Mateo Creek Bridge (1970) where Elliot sculpted the high
piers into a shape that the local community accepted. Surprisingly the resulting
construction bid was lower than the bid on a more conventional and less elegant
design. The prestressed concrete cantilever, or segmented-construction technique,
developed in Germany the 1950s by Ulrich Finsterwalder, has led to many fine
designs in the United States, exemplified by the bridge over the Columbia
River near Portland, Oregon, in which the long-beam spans increase in depth
near the supports to express the increased internal forces present there, and
the vertical piers splay at their bases for the same reason.

In 1976 the state of Washington completed the Pasco-Kennewick Bridge over
the Columbia River, the first major cable-stayed bridge in the United States.
This European innovation has led to many elegant forms, such as the East Huntington
Bridge (1985) over the Ohio River, which, like Pasco-Kennewick, was designed
by Arvid Grant and the German Fritz Leonhardt. Two other examples of cable-stay
bridges are the Dame Point Bridge located in Jacksonville, Florida, for which
Finsterwalder served as consultant to the Howard Needles Tammen and Bergendorf
firm, and the Sunshine Skyway Bridge over Tampa Bay, Florida, designed by
the French engineer Jean Mueller in collaboration with Eugene Figg.

Two unusual engineering design competitions held out promise of enlivening
structural engineering at the start of the twenty-first century. These competitions
required strict rules and a juried decision. The state of Maryland, under
its bridge engineer Earle Freedman, pioneered this process in 1989 for the
U.S. Naval Academy Bridge over the Severn River. The state chose five engineering
firms to compete and named a jury consisting mainly of local civic leaders,
national engineering experts, and the great Swiss designer Christian Menn. Under
Menn's guidance, the process followed the Swiss tradition of such design competitions.
The winning bridge was designed by Tom Jenkins of the Greiner Company.

Based on this success, Maryland stimulated a second engineering design
competition in collaboration with Virginia and the District of Columbia for
the replacement of the rapidly deteriorating and overtaxed Woodrow Wilson
Bridge carrying Interstate 95 over the Potomac River. Four designers competed
and the winning design by the Parsons Transportation Group, using a form inspired
by Menn, once again resulted in an aesthetically superior engineering form.

By 1964 the United States had the four longest-spanning bridges in the
world (Verrazano, Golden Gate, Mackinac [Michigan], and George Washington),
but by 2000 the five longest-spanning structures in the world were all in
other countries. Yet in many states there had appeared smaller bridges showing
the promise that engineering refinement can lead to high-quality American
bridges. Nevertheless, for Americans bridges have served not only as a means
of crossing bodies of water but also as inspirational monuments, evoking feelings of
awe and symbolizing the highest achievements of an engineering culture.

David P. Billington

Bibliography

Billington, David P.,The Tower and the Bridge:
The New Art of Structural Engineering(Princeton Univ.
Press 1985).

Burke, Kathryn W.,Hudson River Bridges(Arcadia 2007).

Dupre, Judith,Bridges: A History of the
World's Most Famous and Important Spans(Black Dog & Leventhal
1997).